Intake manifold structure



March 26, 1935. v. R. HEFTLER INTAKE MANIFOLD STRUCTURE Filed Jan. 20 1!.932 5 Sheets-Sheet l INVENTOR March 26, 1935. v. R. H EFT| ER 1,995,922

INTAKE MANIFOLD STRUCTURE Filed Jan. 20, 1932 s Sheets-Sheet 2 INVENTOR March 26, 1935, v. R. HEFTLER INTAKE MANIFOLD STRUCTURE Filed Jan. 20, 1932 5 sheets-sheet s INVENTOR Patented Mar. '26, 1935 I UNITED STATES 1,995,922 INTAKE MANIFOLD STRUCTURE Victor B. Heftler, Detroit, Mich, assignor, by

mesne assignments, to Zenith Carburetor Company, Detroit, Mich., a corporation of Michigan Application January 20, 1932, Serial No. 587,695 12 Claims. (01. 123-122) The present invention relates broadly to the art of internal combustion engines, and more particularly to improved means for the 'supply' of a combustible mixture thereto under different operating conditions.

In the operation of multi-cylin'der internal combustion engines of usual construction, there is provided an intake manifold of such construction as to effectively cooperatewith each of the various cylinders at one end and to receive a carburetor at the opposite end. In the majority of cases such manifolds are of constant cross sectional area, and the only control for the actual combustible mixture is that afforded by the carburetor throttle. With such structures, and with the throttle only partly or slightly opened, the flow area of the manifold is considerably greater than that required for handling the quantity of mixture which the throttle valve at its then position will pass. This results in an accelerated flow past the throttle followed by a decrease in velocity in the main body of the manifold.

This decrease in velocity is objectionable for a number of reasons, two of which, however, are perhaps more important than the others. In the first place, the decrease in velocity, and particularly with a relatively cold motor, results in the deposit of a portion of the fuel from the air stream so that the engine does not receive the desired fuel quantity or mixture. 4

In the second place, the decrease in velocity results in objectionableeddy currents or nonuniform fiow conditions in difierent portions 'of the manifold, which conditions are frequently reflected in a non-uniform distribution to the different cylinders. Regardless of the exact causes which contribute to the variation in performance of a given manifold under different operating conditions, it is a fact that a manifold which operates most efiiciently at low speeds is not capable of operating at maximum efficiency at high speeds, and vice versa. This necessitates providing a manifold which is usually at least in part a compromise capable of more or less efficiently serving the motor throughout its entire operating range.

It has heretofore been proposed, in an effort to provide a more efficient fuel supply system, to construct a manifold of such nature that its flow area could be increasedor decreased to correspond to different positions of the throttle by physically changing the size of a single flow use of standard intake manifold structures, but their added costv as compared to the advantages gained has not been such as to justify much more than experimental use thereof.

It will be apparent that any construction requiring a physical change in the flow area of a single conduit is objectionable due to the complicated structure provided for effecting the necessary adjustment of the parts and the dimculties attendant upon maintaining the desired tightness of the various joints. For these reasons a divide manifold providing a plurality of flow passages is preferable, and it is to such a construction thatthe present invention relates.

Inasmuch as efficient distribution and motor operation dictate the desirability of supplying a mixture, preformed, through all of the various fiow passages of the manifold, it is desirable that these conduits'all receive, at one end, a mixture of certain predetermined characteristics.- This may be most effectively accomplished by the conduits in use at any time is left under the con-- trol of the operator, it is not only possible, but,

probable, that throughout the major portion of the operation of the motor the adjustment made by the operator will not be theoretically correct for the actual flow, thus defeating the full ad'- vantages of a divided manifold. To this end I provide'means responsive to engine conditions for automatically controlling the flow area at any instant, while alwaysproviding a flow conduit of minimum cross sectional area capable of giving eflicient low speed performance.

The art has heretofore recognized the advan- .tages of preheating a combustible mixture as supplied to a motor. This preheating also involves difliculties. If a single manifold is made large enough to supply the maximum volume required by the motor at any time with the entire mixture heated, it is unduly large for any low speed operation. If it is made small enough for eflicient low'speedoperation with a heated charge, the

invention therefore contemplates not only a divided'manifold, but a manifold characterized temperatures, the construction preferably being such that there is a comparatively high temperature charge supplied for low speed operating conditions with a relatively lower temperature .by divisionswhich may be operated at different a charge at all higher speeds. This condition may be effectively obtained by providing a manifold having conduits adapted to supply a mixture at relatively different temperatures and so constructed that the highest temperature conduit is always open to provide a flow passage of definite predetermined area extending from the carburetor to the motor. To this end the construction preferably comprises a constantly open relatively hot conduit with a normally closed relatively cold conduit, which relatively cold conduit may be opened more or less automatically in accordance with the requirements of the engine.

I have further found that with an automatic control, such as one responsive to suction conditions above the throttle, it is desirable to preclude the possibility of any excessively rapid change in the position of the control valve with consequent chattering of the valve and corresponding pulsations in the mixture being supplied. To preclude such a possibility, I preferably provide a valve responsive to suction, but controlled in part through the medium of a dashpot effective for dampening or checking excessively rapid movements thereof.

In the accompanying drawings I have shown for purposes of illustration only, certain preferred embodiments of my invention. In the drawings:

Figure 1 is a side elevational view, partly broken away, of a manifold constructed in accordance with the present invention;

Figure 2 isa side elevational view of the relatively cold conduit and control casing;

Figure 3 is a front elevational view of the structure of Figure 2; v

Figure 4 is a bottom plan view of the structure of Figures 2 and 3;

Figure 5 is a vertical sectional view on an enlarged scale through the valve casing of Figures 2 and 3;

Figure 6 is a partial top plan view, partly broken away, of a portion of the exhaust manifold showing the relatively hot manifold formed integrally therewith; r ,4

Figure '7 is a transverse sectional view on the I line VII-VII of Figure 6;

Figure 8 riser;

Figure 9 is a side elevational view of the carburetor riser;

Figure 10 issa transverse sectional view on the line X-X of Figure 1;' and Figure, 11 is a detailed sectional view illustrating a slightly modified form of closure for the upper end of the valve casing.

In accordance with the present invention, there is provided an exhaust manifold 2 of any usual construction but preferably having formed integrally therewith a conduit 3, as illustrated more particularly in Figure 6, adapted to constitute the relatively hot conduit of an intake manifold. At substantially its mid portion, the conduit 3 is shaped to provide a lower flange 4 adapted to cooperate with the upper flange 5 of a carburetor riser 6 illustrated in Figures 8 and 9. Opposite the flange 4 the conduit 3 is formed with an upper flange 7, as shown in Figure 6, adapted to receive a flange 8 formed on a relatively cold conduit as is a top plan view of the carburetor illustrated more particularly in Figure 4 of the drawings.

Extending continuously between the flanges 4 and 7 is a through passage 9 adapted to aline with the passage 10 through the carburetor riser 6 and to aline with a passage 11 in a valve casing 12 formed integrally with the flange 8 of ,therelatively cold conduit. Formed in diametrically opposite sides of the through passage 9 are ports 14 leading to the opposite flanges of the relatively hot conduit 3.

The riser 6 is in turn formed with a bottom flange 15 adapted to cooperate with the upper flange 16 of a carburetor 17 of any desired construction. The relatively hot conduit 3 is formed with extensions 18, as illustrated in Figure 1, projecting downwardly a suflicient distance to cooperate with the intake ports of a motor, as in usual structures. Extending laterally from the valve casing 12 are similar passages 19 of such length as to cooperate with the extensions 18 and also deliver a combustible mixture to the inlet ports of the motor, the extensions 19 being provided with attachingfianges 20 forsecuring the same in position. These extensions 19 communicate with the valve casing through diametrically opposite ports 21, which ports are so disposed as to lie in the path of travel of a valve 21a disposed within the valve casing. This valve is illustrated in Figure 5 as comprising a piston carried by a stem 22 extending through a second piston 23. The pistons 21a and 23 are disposed within the valve casing 12 on opposite sides of a stop ring '24 adapted to be held in position by screws 25.

Carried by the stop ring is a centering sleeve 26 through which the stem 22 moves. Bearing at one end against the sleeve 26 and at its opposite end against the underside of the upper piston 23 is a spring 27 normally tending to urge the parts into the position illustrated in Figure 5. Also cooperating at its lower end with the sleeve 26 is a second spring 28 of relatively lighter construction than the spring 2'7 and of less length and serving to check] downward movements of the valve 21 as will be hereinafter more clearly apparent.

The upper end of the valve casing 12 is closed by a cap 29 having a port 30 therethrough communicating with the atmosphere and subjecting the upper surface of the piston 23 to atmospheric within the manifold at a point intermediate the,

engine and the carburetor throttle (not shown) provided on the throttle shaft 31. Due to this construction, if the throttle is in its partly opened position as in the case of idling or slow speed running, there will be a comparatively high vacuum, or low absolute pressure in the space-intermediate the throttle and the engine. This pressure will, in any case, be sufficiently lower than atmospheric pressure so that the atmospheric pressure existing on the upper surface of the Cuppe'r piston 23 will lower this piston against the action of the spring 27 and thereby lower the piston valve 21a'into a positionwhere it will cover the ports 21 and thereby cut off communication between the carburetor and the extensions the upper end of the inner spring 28 will come into-engagement with a washer 32 and thereby cushion the further downward movement of the pistons. This (downward movement will ultimately be checked either by the engagement of the skirt 33 of the piston 23 with the upper side of the stop ring 24, or by the engagement of a stem collar 34 with the upper end of the sleeve 26, depending upon the setting of the parts. In

.' either case the maximum movement of the pistons in both directions will be definitely controlled. The extent of upward movement is preferably only such that the ports 21 may be completely uncovered while the extent of downward movement is slightly greater than that required to Band the extensions 18 tothe inlet chambers of operation, or when it is continued in operation atively cold conduit will be out off from communication with the motor by the piston valve 21a, thereby enabling a combustible mixture to be furnished from the carburetor through the riser 6 to the motor only by way of the relatively hot conduit 3. This conduit will be initially designed with a flow area such as to insure desirable fiow conditions to 'the motor and with sufiicient flow area so as to furnish the motor with the desired mixture during low speed operation thereof.

If the throttle is suddenly opened, the absolute pressure in the intake manifold between the throttle and the motor will rise to such an extent thatthe suction will not be great enough to hold the piston valve 21a in its lower position against the action of the spring 27. The pistons 21d and 23 will therefore move into the position shown in Figure 5 with a speed of movement directly controlled by the rapidity with which the air above the piston 23 is permitted to escape through-the atmospheric vent 30. By making this vent sufficiently small, the upward movement of the piston assembly may be effectively controlled.

At intermediate throttle positions, the valve 21a may assume intermediate positions corresponding more or less exactly to the suction conditions within the manifold, thereby providing a flow area through the relatively cold conduits which is directly proportioned, automatically, to the engine requirements.

In some cases it may be desirable to so restrict the upward movement of the valve assembly until such time 'as the temperature adjacent the motor, or under the hood in the case of an automobile, has reached a predetermined point. If such is the case, I may utilize the construction illustrated in Figure 11 wherein there is shown a modified form of cap 29' for the valve chamber. In this embodiment the cap is formed with a through opening 36 into which is threaded a valve holder 37 provided with a port 38 terminating in a seat 39 from which projects a valve retaining sleeve 40.

, Within the valve retaining sleeve is a ball valve 41 normally held in the position illustrated in Figure 11 by a bi-metallic finger 42. As the temperature to which the bi-metallic finger 42 is subjected rises, the finger will bend downwardly,

thereby lowering the valve 41 within its s1eeve40.

against the seat 39. In this position the upward movement of the piston assembly will be precluded. Downward movement, however, will be permitted to the extent required to permit lowering of the piston assembly within the casing 12. During such lowering movement, atmospheric pressure will unseat the valve 41 against the action of the bi-metallic .finger 42 and permit atmospheric pressure to flow past the valve'and through the ports 43 into the valve chamber 12. With this construction, it is possible to con-- tinue operation of the motor utilizing only' the relatively hot conduit 3 until such time as the entire motor has reached a predetermined operating temperature sufiicient to insure deflection of the finger 42.

Under normal conditions of operation, assuming the motor to have reached an operating temperature, it will be supplied during idling and low speed entirely through a relatively hot conduit of fixed cross'sectional area which is always free- 1y open to provide free communication between the carburetor and the motor and effective for delivering a combustible mixture from the carburetor to the motor in heated condition, due to the intimate heat transfer relationship between the conduit 3 and the exhaust manifold 2. When, however, the operating conditions of the motor require a greater mixture flow, the valve assembly including the valve 21, will automatically rise vto,the extent determined by'the increase in absolute pressure within the manifold corresponding to the position of the throttle.

To this extent there will be provided an auxiliary flow conduit in parallel with the relatively hot conduit and communicating at its opposite ends respectively with the carburetor and motor with which the relatively hot conduit communicates. The auxiliary fiow conduit; therefore, will be effective for delivering a combustible mixture of the same characteristics as that supplied by the relatively hot constantly open conduit, the mixture at difierent temperatures uniting in the inlet chambers of the motor from which it is auxiliary conduit or may have a less area or greater area than the flow conduit. In mostcases, however, I have found that the most satisfactory results are obtained by providing a relatively hot conduit having a flow area which does not exceed that of the auxiliary conduit and which is preferably somewhat less than that of the auxiliary conduit. In this manner a higher velocity flow of heated mixture is rendered available for all idlingand low speedrunning periods of the motor.

The advantages ofthe invention arise from the provision of an intake manifold adapted to receive a combustible mixture from a carburetor and deliver it to an engine, and characterized by the division of the manifold into a plurality of relatively separate conduits terminating at one end in a position adjacent acarburetor' throttle and at the opposite end communicating with the inlet chamber or-chambers of an internal combustion engine, with one of the conduits continuously open to provide a fixed flow area for idlir'g and low speed running conditions, together a constantly open conduit for furnishing the mixture to the motor at relatively high temperature during such periods of time as full power from the motor is not required. In this manner there is obtained an efiicient vaporizing of the liquid fuel at low speeds. At high speeds, if the single conduit were utilized, the heating of the charge would so expand the air that a given unit of volume would have materially less weight than that required for full power. In accordance with the present invention, when full speed is desirable, a supplemental conduit automatically comes into operation thereby furnishing the full volume and weight of air required for such operating condi- 'tions.

Still further advantages arise from the provision of automatic controlling means so constructed and regulated as to preclude undesirable chattering or hammering movements thereof.

While I have herein'illustrated' and described certain preferred embodiments of the invention, it will be understood that changes in the construction and operation of the parts may be made without departing either from the spirit of the invention or the scope of my broader claims.

I claim:

1. The combination with a carburetor, of a manifold adapted to receive a combustible mixture from the carburetor and deliver it to an engine, characterized by the division of the manifold into a plurality of separate 'conduits, a throttle valve intermediate the carburetor and the manifold, one of said conduits being continuously open, and means responsive'to the diiference between atmospheric pressure and the pres sure in the manifold for controlling the number of conduits additionally to said constantly open conduit which are available at any time for mixture delivery.

2. The combination with a carburetor, of a manifold adapted to receive a combustible mixture from the carburetor and deliver it to an engine, characterized by the division of the manifold into a pair of separate conduits, a throttle valve intermediate the carburetor and the manifold, one of said conduits being continuously open, and means responsive to the suction of the engine between the throttle and engine and ex- ;posed to the atmosphere for controlling the flow through the second conduit of said pair.

3. The combination with a carburetor, of a manifold adapted to receive a combustible mixture from the carburetor and deliver it to an engine, characterized by the division of the manifold into ,a pair of separate conduits, a throttle f valve intermediate .the carburetor and the manifold, one of said conduits being continuously 'open, and means responsive to the suction of the engine between the throttle and engine for controlling the flow through the second conduit of said pair, said means comprising a valve movable in response to the suction to which it is subjected, said valve having one side only in communication with the engine.

4. The combination with a carburetor, of a manifold adapted to receive a combustible mixture from the carburetor and deliver it to an engine, characterized by the division of the manifold into a pair of separate conduits a throttle valve intermediate the carburetor and the manifold, one of said conduits being continuously open, means responsive to the suction of theengine between the throttle and engine for controlling the now through the second conduit of said pair, and 5 means for regulating the speed of movement of said conduit controlling means.

-5. The combination with a carburetor, of a manifold adapted to receive a combustible mixturefrom the carburetor and deliver it to an en- 1 gine, characterized by the division of the manifold into a plurality of separate conduits, a throttle valve intermediate the carburetor and the manifold, one of said conduits being continuously open, means responsive to the operation of the 15 fold into a plurality of separate conduits, a throt- 25 tle valve intermediate the carburetor and the manifold, one of said conduits being continuuously open, and means responsive to the suction of the engine between the throttle and engine for controlling the number of conduits addi- 30 tionally to said constantly open conduit which are available at any time for mixture delivery, said means comprising a valve having one side exposed to the atmosphere.

7. The combination with a carburetor, of a man- 35 ifold adapted to receive a combustible mixture from the carburetor and deliver it to an engine, characterized by the division of the manifold into a plurality of separate conduits, a throttle valve intermediate the carburetor and the man- 40 ifold, one of said conduits being continuously open, means responsive to the suction of the engine between the throttle and engine for controlling the number of conduits additionally to said constantly open conduit which are vailable 45 at any time for mixture delivery, and means for regulating the speed of movement of said conduit controlling means. L

8. The combination with an exhaust manifold having secured thereto in heat conducting rela- 5 tionship an intake conduit provided with a plurality of branches terminating adjacent to the intake valves, of a carburetor adapted to supply a combustible mixture to said conduit, a throttle valve intermediate the carburetor and said conduit, a second conduit extending generally parallel to said first mentioned conduit throughout adapted to receive a mixture supply from said carburetor, said second condluit beingin' less efiicient heat transfer relationship to the ex- 60 haust manifold than the first conduit, means cooperating with said second conduit only for controlling the effective flow area thereof, said last mentioned means comprising a control valve auto matically movable in response to the operation of 65 the engine supplied by said carburetor, and means for controlling the movement of said valve.

9. The combination with an exhaust manifold having an intake conduitsecured thereto inheat conducting relationship, a carburetor adapted to supply a combustible mixture to said conduit, a throttle valve intermediate the carburetor and said conduit, a second conduit adapted to receive a. mixture supply from said carburetor, said second conduit being in less efllcient heat transfer relationship to the exhaust manifold than the first conduit, means cooperating with said second conduit only for controlling the efiective flow area thereof, said last mentioned means comprising a control valve automatically movable in response to the operation of the engine supplied by said carburetor, and thermostatically operated means for controlling the movement of said valve.

10. An intake manifold comprising a plurality of conduits connected in parallel and adapted to communicate with a carburetor at one end and deliver a combustible mixture to an engine'at the other end, and means including a dash-pot and valve therein automatically responsive to the operation of the engine to which said manifold is attached for controlling the flow area of one of said conduits only.

11. An intake manifold comprising a plurality of conduits connected in parallel and adapted to communicate with a carburetor at one end and deliver a combustible mixture to an engine at the other end, and means including a dash-pot and valve therein automatically responsive to the operation of the engine to which said manifold is attached for controlling the flow area of one of said conduits only, there being means for heating one of said conduits to a higher temperature than the remaining conduit.

12. The combination with a carburetor, of a manifold adapted to receive a combustible mix-' ture from the carburetor and deliver it to an engine, characterized by the division of the manifold into a plurality of separate conduits, a throttle valve intermediate the carburetor and the manifold, one of said conduits being continuously open, and means including a valve having one side under the influence of the mixture pressure and the other side outside the influence of the mixture pressure for controlling the number of conduits additionally to said constantly open conduit which are available at any time for mixture delivery.

V VICTOR R. HEFTLER. 

